The only castle in North America to ever house European sovereigns.

The famous artist couple lived and worked here, in two different houses connected by a bridge.

66,000 pieces of art, donated by one of the world's richest men.

Frida Kahlo's childhood home, now a museum of her life and works.

An antiquated German apothecary on Chicago's North Side.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

Illegal drag racing two stories beneath Chicago’s streets.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A monument to the man who almost killed Hitler.

The bunker where Hitler took his own life is hidden under this deliberately ordinary parking lot.

Metro station with a claim to rock n' roll fame.

One of downtown Berlin's last reminders of its Communist past.

Where once there was a train station bathroom, there is now this German burger joint.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A fascinating insight into daily life in the Eastern Bloc.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

A space dedicated to contemporary art and culture, co-chaired by fashion icon Miuccia Prada.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

The secret medieval communication system will whisk your words above the noise of the crowd.